Dynamic Fabric Automation (“DFA”), also referred to as “Vinci,” is an architecture for facilitating data center networking. The physical topology of DFA is based on a two-tier fat tree, also known as a Clos network, in which a plurality of leaf nodes (which may be implemented as Top of Rack (“ToR”) switches or routers) connects to each of a plurality of spine nodes (implemented as switches or routers) and vice versa. To support data forwarding, IP fabric is used in one embodiment of DFA. Additional details are provided in “VXLAN: A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks” (draft-mahalingam-dutt-dcops-vxlan-02), which is hereby incorporated by reference in its entirety.
Virtual eXtensible Local Area Network (“VXLAN”) is a technique for providing an L2 overlay on an L3 network. VXLAN encapsulates native data frames with a VXLAN header and uses UDP/IP for transportation. The VXLAN header contains a VXLAN segment ID/VXLAN network identifier, which is a 24-bit field that identifies virtual network segments for different tenants. Multi-destination frames in VXLAN are carried in IP multicast data packets, which use group addresses as destination IP addresses. A group address can be dedicated to one segment or shared among multiple segments. Additional details are provided in “VXLAN: A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks” (draft-mahalingam-dutt-dcops-vxlan-02), which is hereby incorporated by reference in its entirety. One of the major advantages of VXLAN is that core routers comprising the underlay network can be implemented using generic IP routers that have no knowledge of the overlay encapsulation. In DFA IP fabric, spine routers may be VXLAN-unaware and are therefore presumed not to perform pruning on VXLAN segment ID.